在某些情况下,气体探测器的工作气压要求有很好的稳定性.例如,电离室、正比计数管、G-M计数管等用于探测很低能量的带电粒子时(如10—20keV的β粒子),要求窗薄到约1μg/cm2.当它们在真空中使用并需连续长时间积累数据时,工作气体会通过窗渗漏引起气压下降,从而使其工作状态改变 In some cases, the working pressure of the gas detector requires good stability, for example, ionization chamber, proportional counter tube, GM counter tube for detecting very low energy charged particles (such as 10-20keV β Particles), requiring windows to be thinned to about 1 μg / cm2.When they are used in a vacuum and need to accumulate data for a long period of time, the working gas can cause a pressure drop through the leaks in the window, changing its operating state